Monoesters of phosphonic acids



United States Patent Oil 3,350,480 MONOESTERS F PHOSPHONIC ACIDS Emile Cherbuliez and Joseph Rahinowitz, Geneva, Switzerland, assignors to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York No Drawing. Filed Nov. 24, 1965, Ser. No. 509,641 6 Claims. (Cl. 260-961) This is a continuation-in-part of United States patent application Ser. No. 230,315, filed Oct. 11, 1962, now US. Patent No. 3,268,629.

The present invention relates to new phosphonic monoesters and to an improved example, by the acid according to the equation:

0 0 0 =Ri i R 21101 01 HO in which R represents an aliphatic, aromatic or heterocyclic radical, usually of 1 often of 2 on corresponding dichlorides.

It is suflicient to (R-PO with 0.5 to 3 moles, especially with 1.2 to 3 preferably between 50 and 150 degrees centrigrade, and the reaction may also be carried out under vacuum. The mixture becomes homogeneous and the phosphonic monoester is obtained, as exemplified by the following equation:

Generally, the phosphonic monoester is separated from the mixture in the form of its salt which may be characterized by the formula In the above formulas, R has the significance indicated previously, R represents aliphatic radicals such as alkyl,

3356,48 Patented Oct. 31, 196

ice

aromatic or araliphatic radicals such as a phenyl or benzyl radical. These substitphonated.

Thus, this reaction is or in multiple. The reaction is more rapid than with secondary alcohols, thus, heating time will be desirable during phosphonation ary alcohol.

A preferred embodiment of this invention is the reaction of acid in the presence alkylamine, e.g.,

of a tertiary base, such as tri-lower triethylamine or trimethylamine cyclic tertiary base, such as an equivalent of the said tertiary base is especially advantageous if the aliphatic alcohol acid, such as a terpene alcohol.

If the radical R is the radical of an a-nitrilo alcohol, the nitrile group may be hydrolyzed to form an ester of an a-carboxamido alcohol. If the reaction mixture does not contain any water, there may be intermediate formation of a cyclic derivative of the ester, which is easily hydrolyzed with water to form the monoester of the ucarboxamido alcohol. With 6-, and zS-nitrilo alcohols the monoesters of the nitrilo alcohols are preferably obtained; the hydrolysis to the carboxamido derivative does not take place.

The monoesters obtained can be isolated as their metal salts. The alkaline or alkaline earth metal salts of phosphonic monoesters are practically neutral in aqueous solution (pH about 6) and can be preserved indefinitely in a queous solution (at this pH the time of half-hydrolysis 1 a 0.1 molar aqueous solution of ester at 100 degrees entigrade is greater than 500 hours); the salts of phoshonic monoesters of amino alcohols are alkaline in aqueus solution (pH 10.5-11) and also are stable at this pH.

In order to isolate the alkaline earth metal or alkali netal salts of the phosphonic monoester, including the :alcium, barium, strontium, sodium, potassium, lithium, tluminum and magnesium salts, one proceeds as follows:

After cooling, the excess alcohol is distilled (when a .arge excess is used) under vacuum. The residue is taken 1p by water and neutralized by a hydroxide of an alkaline earth metal to a pH of 8.2 (turning of phenolphthalein). (In the case of amino alcohols, it is desirable to add hydroxide sufficient to obtain a pH of about 11.) The phosphonic acid which may still be present (formed by hydrolysis of the oxide which may not have reacted, or formed in the course of the reaction when polyphosphonic acid is used) precipitates partially as an alkaline earth \metal salt; it is completely precipitated by the addition of one volume of alcohol. This is filtered and the filtrate which contains the alkaline earth metal salt of the phosphonic monoester is evaporated and dried under vacuum. Generally, the product obtained is pure. If not, it is purified by extraction with boiling acetone (which dissolves the impurities); after cooling, the alkaline earth metal salt of the phosphonic monoester is filtered.

If it is desired to obtain alkali metal salts of these monoesters, the alkaline earth metal is dissolved in water and there is added the required quantity of carbonate of an alkali metal. The precipitate of the alkaline earth metal carbonate formed is filtered off and the filtrate is evaporated to dryness under vacuum. The amorphous residue treated by acetone is transformed into a crystalline precipitate which is the alkali metal salt of the monoester. One may adapt the above methods to make other salts.

The alkaline earth metal salts of the phosphonic monoesters of superior aliphatic alcohols or of terpene alcohols are generally insoluble in water or in 50 percent ethyl alcohol. In order to isolate these monoesters, one proceeds preferably as follows:

(a) After cooling, the reaction mass is taken up by ether and neutralized by triethylamine. The triethylammonium salt of the phosphonic acid is filtered off, whereas the triethylammonium salt of the phosphonic monoester is soluble. The ether and the excess of the tertiary base are distilled, the residue is taken up by ether and the alkali earth metal salt of the phosphonic monoester is precipitated by adding an aqueous solution of the corresponding alkali earth metal halogenide. The precipitate is washed with water and is purified as previously described.

(b) If the reaction is carried out in the presence of a tertiary base such as trimethylamine, triethylamine or pyridine, the reaction mixture is taken up by ether and the phosphonate of the tertiary amine is filtered off. The ether and the excess of the tertiary base are distilled and the residue is taken up by water. The alkaline earth metal salt of the phosphonic monoester is precipitated by adding an aqueous solution of an alkali earth metal halogenide.

If the free phosphonic monoester crystallizes easily, the reaction mixture is taken up by water and the free phos phonic monoester is precipitated by adding a strong acid, such as hydrochloric acid (this is the case, for instance, of methyl phenylphosphonic acid).

This new process of phosphonation of alcohols by phosphonic oxides and polyphosphonic acids has a number of advantages: it leads straight to monoesters only, it is simple and directly gives pure products in very high yield, calculated as a percentage of the theoretical value. Moreover, the process is quite general and many of the prepared phosphonic monoesters are new.

The monoesters thus obtained and their salts may be used as additives to liquid fuels, such as gasoline, or as products for impregnating fibers so as to make them fireproof, pest-resistant or vermin-proof.

The invention is illustrated but not limited by the following examples. All parts are by weight and all temperatures are in degrees centigrade, unless otherwise indicated.

Example 1 140 parts (1 equivalent) of phenylphosphonic oxide (C H -PO and 48 to 64 parts (1.5 to 2 moles) of anhydrous methanol are heated to degrees Centigrade (bath temperature). After cooling, the excess alcohol is evaporated under vacuum and the residue is taken up with 500 to 800 parts of H 0. This solution is neutralized by Ca(OH) (or Ba(OH) if one desires to obtain a barium salt of the monoester) up to a pH at which phenolphthalein turns to colored form (about 8.2). Then an equal volume of alcohol is added and the calcium (or barium) phenylphosphonate thus precipitated is filtered. The filtrate, evaporated to dryness, yields the monomethylphenylphosphonate of calcium (or barium) which is generally pure initially. If it is not, the dry residue is dissolved in boiling acetone and, after cooling, the calcium or barium monomethylphenylphosphonate is filtered. The yield in pure product,

is 77 percent of theoretical.

Instead of phenylphosphonic oxide, other aryl phosphonic oxides may be employed to obtain corresponding salts of aryl phosphonic monoesters.

in Example 1.

The monoester of ethanol of the formula:

ll/ C Hr-P-O 0 m Yield=84 percent.

Yield-:56 percent.

The monoester of butanol of the formula:

Yield=75 percent.

The monoester of isobutanol of the formula:

0 OM otHti o 011(0119-01110113 Yield:60 percent.

The monoester of amyl alcohol of the formula:

0 OM C0H5%{-0 CHzCHzClLCHaCH;

Yield-=71 percent.

In all the above formulas M is Ca or B305.

Example 3 in an oil bath, 140 parts (1 mole) of phenylphosphonic acid are heated gradually to 200 degrees centigrade (bath temperature) and are kept for about 48 hours to 72 hours methyl orange and phenolphthalein greatly diminishes). are introduced with the operation being continued in the manner described in Example 1. There is obtained a phenylphosphonic monoester in the form of its barium or calcium salt, described under Examples 1 and 2, with yields of 51 percent for the methyl monoester, 44 percent ester, 22 percent for the isopropyl monoester, 40 percent for the butyl monoester, 27 percent for the isobutyl ester and 22 percent for the amyl ester. These yields are clearly below those obtained with the oxides (Examples 1 and but as in the Examples 1 and 2, one may recover all phenylphosphonic acid which is not transformed into an ester, in the form of an alkaline earth metal salt.

Example 4 140 parts (1 equivalent) of phenylphosphonic oxide and 84 to 112 parts (1.5 to 2.0 moles) of propargyl alcohol are heated to 90 degrees centigrade. One then isolates the monopropargylphenylphosphonate of barium or calcium in the manner already described in Example 1. It is illustrated by the structural formula:

OM CGH5PQO CHz-CECH and the yield is 70 percent.

By infrared spectroscopic examination, the presence of the -CEC- group is verified.

In the same manner, there is prepared in 90 percent yield, phenylphosphonic monoester of allyl alcohol oflH-P=0 0CH2OH=CH2 All of these are new products. In the above formulas M=Ca or Ba Example 5 140 parts (1 equivalent) of phenylphosphonic oxide and 120 to 161 parts (1.5 to 2.0 moles) of 2-chloroethanol are heated for 16 hours at 120 degrees centigrade (bath temperature). After cooling, the excess of chlorohydrin is distilled off under vacuum and one isolates the barium salt of the mono (2-chloroethyl)phenylphosphonic acid,

6 Yield=65 percent.

Phenylphosphonic monoester of 1,3-difiuoropropanol-I degrees centigrade, 48 hours) of the formula:

OOM

O CH(CH2F)2 Yield=56 percent.

Phenylphosphonic monoester of 3-fiuoropropanol-l (100 degrees centigrade, 48 hours) of the formula:

OCHZCH2CH2F Yield=40 percent.

Phenylphosphonic monoester of 2,2,3,3-tetrafiuoropropanol-l (100 degrees centigrade, 48 hours) of the formula:

OOM

O CH2CFgCHFz Yield'=60 percent.

All of these are new products. In the above formulas M=Ca or Ba Example 6 parts s 5 z)n glycol are heated 48 hours at 100 degrees centigrade (bath 0 OH CsH5li. -O CHZCHZOH in the manner described in Example 1, with a yield of 60 percent.

In a similar manner, except as it relates to the temperature for the tetramethyleneglycol, there are prepared the alkaline earth metal salts of phenylphosphonic monoesters of diols mentioned below with the yields indicated:

'Phenylphosphonic monoester of propanediol-1,3 of the formula:

o H Po CHZCHZCHZOH Yield=65 percent.

The phenylphosphonic monoester (here the reaction takes place at 50 for 48 hours) of the formula:

OOM

of butanediol-1,4 degrees centigrade,

OOIIzCHzCHzCHzOH Yield=72 percent.

Phenylphosphonic monoester of pentanediol-l,5 of the formula:

0 OM H/ C5H5-P O CHzCHgCHzCHzCHzOH Yield=77 percent.

the phosphonation process.

Also, even if there is used a large excess of a phosphonating agent, only one group OH is phosphonated.

All of these esters are new. In the formulas given M=Ca or Ba Example 7 140 parts (1 equivalent) of phenylphosphonic oxide and 267 to 336 parts (3 to 4 moles) of dimethylcolamine (dimethylaminoethanol) are heated for 3 hours at 120 degrees centigrade. The excess of dimethylcolamine is distilled off under vacuum and the residue is dissolved in 800 to 1000 parts of water. There is then added an excess of calcium hydroxide in suspension in water with the mixture being agitated for several minutes. After filtering, one volume of alcohol is added to the filtrate to completely precipitate the calcium phenylphosphonate still present. This is followed by further filtration and evapora tion under vacuum. An amorphous residue is obtained, which, after being treated with boiling acetone, cooled and filtered, yields a precipitate of calcium dimethylaminoethylphenylphosphonate. The formula of this compound is O Cam ll CgHr-P 0 CH2CH2N(CH3)2 and it was obtained in 50 percent yield.

In treating l-diethylaminopropanol-Z in the above described manner, there is obtained by evaporation under vacuum an aqueous alcoholic solution of calcium (l-diethylaminopropyl-2)phenylphosphonate,

O 0 Cam o CH-OH CH2N (CzHs) 2 which is pure. The yield is 30 percent.

Example 8 140 parts (1 equivalent) of phenylphosphonic oxide and 152.5 (2.5 moles) of colamine are heated at 180 degrees centigrade (bath temperature) up to the point where the mass becomes homogenous. Then a vacuum is created in the flask, which is kept at this temperature overnight. After cooling, the reactive mass is dissolved in 800 to 1000 parts of water with the addition of an excess of calcium hydroxide. This mixture is agitated and an equal volume of ethanol is added. The liquid is filtered and evaporated dry under vacuum. The residue is treated with boiling alcohol and yields, after cooling, a precipitate of calcium (2-aminoethyl) phenylphosphonate,

(fi/O 030.5 C H -P 0 CHzCHzNHz in 40 percent yield.

Example 9 140 parts (1 equivalent) of phenylphosphonic oxide, 79 parts (1 mole) of pyridine and 111 to 148 parts (1.5 to 2.0 moles) of tertiary butanol are heated for one night at 75 degrees centigrade (bath temperature). A calcium or barium aslt of t-butylphenylphosphonic acid ll Cally-J? O C (CHrDa is obtained in a yield of 60 percent by isolation in the manner described under Example 1.

Example 10 One mole of cetylic alcohol and one equivalent of phenylphosphonic oxide are heated for 48 hours at 110 degrees centigrade. After cooling, the reaction mixture is taken up by ether and four equivalents of triethylamine are added. The precipitate of triethylammonium phenylphosphonate is filtered off, whereas the triethylammonium salt of the monoester is soluble. The ether and excess of triethylamine are evaporated under reduced pressure and the residue is taken up by ether. This solution, treated with aqueous barium chloride, yields a gelatinous precipitate which is filtered off, washed with water and then with acetone and ether, and finally dried in vacuum over P 0 O O Baas Calls-P O CH2(CH2) 4CH3 When cetyl alcohol, used as starting material in the above example, is replaced by one of the alcohols of the following formulas: CH (CH CH OH CH (CH CH OH CHF (CF CH OH and when using the described procedure, the following barium phenylphosphonic monoesters are obtained:

0 OBS/0.5

O CH2(GH)5CH3 Yield=55 percent.

0 OBBus C H -P O CH2(CH2)CI'I3 Yield=23 percent.

Oak-1 O CII2(CF2)9CIIF2 Yield=55 percent.

Example 11 One mole of nerol, two moles of triethylamine and one equivalent of phenylphosphonic oxide are mixed carefully (the reaction is exothermic and it is necessary to cool). After a few minutes the mixture becomes homogenous. It is then heated at degrees centigrade for 15 hours (with good agitation). After cooling, the reaction mass is taken up by anhydrous ether. The triethylammonium phenylphosphonate is filtered off and the ether and the excess of triethylamine are evaporated under reduced pressure. The oily residue is dissolved in water and the pH brought to about 5, by adding dilute hydrochloric acid. When an excess of a concentrated aqueous solution of calcium chloride is added to the preceding solution, voluminous precipitate of the calcium salt of the phenylphosphonic monoester appears. This precipitate, which retains most of the unreacted terpene alcohol, is washed with water and then with acetone which dissolves most of the retained alcohol. To achieve the elimination of the retained alcohol, the precipitate is finally washed with ether and then dried in vacuo over P 0 The yield is 30 percent of pure calcium neryl phenylphosphonate C H O PCa In a similar manner, the calcium salts of the phenylphosphonic monoesters of geraniol and farnesol are obtained in 31 percent yield each.

Example 12 Three moles of menthol, 3 moles of pyridine and 3 equivalents of phenylphosphonic oxide are mixed very carefully until the mass liquefies and becomes homogenous. The mixture is then heated for 15 hours at 7075 degrees centrigrade. After cooling, the reaction mixture is taken up by water. This solution is introduced slowly and with agitation in normal hydrochloric acid (3 liters). The precipitate of menthylphenylphosphonic acid is filtered off, washed with water and then heated at 60 degrees centrigrade, in vacuo, for one night, in order to eliminate any trace of menthol which has been retained by the precipitate. In this manner, pure menthyl phenylphosphonic acid, C I-1 0 1, melting point 91 degrees centigrade, is obtained in an 81 percent yield.

In a similar manner, bornyl phenylphosphonic acid, C H O P, melting point 104-105 degrees centigrade, is prepared from borneol in an 88 percent yield.

Example 13 One mole of lactonitrile and one equivalent of phenylphosphonic oxide are heated at The a-nitrilo alcohols are transformed, under the described conditions, into the corresponding carboxamidoalkyl phenylphosphonic monoesters, [3-, 'yand fi-nitrilo alcohols yield the corresponding nitriloalkyl phenylphosphonic monoesters.

In a similar manner are phosphonated the nitrilo alcohols of the following formulas (yield of the barium salt of the monoester in parenthesis): NC-CH OH (35%); NCC(CH OH (64%);

NC-CH (CH CH OH (34 NCCH CH CH OH 5 8 Example 14 One mole of anhydrous glycerol and one mole of phenylphosphonic oxide are heated at 165 degrees centigrade until the mass liquefies, and then for hours at 120 degrees centrigrade. The manner described in Example 1, yields crude barium glyceryl phenylphosphonate. The crude salt is reduced to a Cl HO very fine powder which is heated for a few minutes with absolute alcohol. After cooling, one Volume of acetone is added and the precipitate filtered 01f, Washed with alcohol and vacuum dried. These operations are repeated on this product until pure barium glyceryl phenylphosphonate is obtained. The yield is 49%.

HOCH CHOHCH OP(O) (C H OBa barium a-glyceryl phenyl-phosphonate HOCH CH[OP (O) (C H (OBB ]CH OH barium fi-glyceryl phenylphosphonate.

The determination of the neighboring -OH groups by the method of Malaprade indicates that the product is composed of 51.5% of barium a-glyceryl phenylphosphonate and of 48.5% of the ,B-derivative.

Example 15 Six moles of tribromoethanol and 4 equivalents of phenylphosphonie oxide are heated at 90 degrees centigrade for 44 hours. After cooling, the reaction mass is taken up by cold alcohol or acetone and poured immediter to five liters. One volume of alcohol is added and the barium phenylphosphonate is filtered off. The filtrate is evaporated to dryness under vacuum, and the residue treated with ether (in order to dissolve any traces of reit) tained tribromoethanol) yields the pure barium tribromo ethyl phenylphosphonate having the following formula:

In a similar manner are prepared the phenylphosphonic monoesters of trichloroethanol, trichloroisopropanol and trifluoroethanol:

CCl CH OP(O)(C H )(OBa0,5) Yield: 88% cc1 cH 0P(o)(C6H5)] OBa0.5)CH Yield: 78% CF3CH2OP(O c n oBaM) Yield: 81%

Example 1 6 RP(O) (OM)(OCH (70%) 3)3 (53%) 2 5)( 3) HOCH CH CH OP(O) (R)(OM) (70%) ClCH CH OP(O)(R)(OM) (62%) CH (CH CH OP(O)(R) (OM) (62%) H NCH CH OP(O) (R) (OM) (53%) (CH NCH CH OP(O)(R) (OM) (30%) H NCOCH(CH )OP(O)(R) (OM) (38%) NCCH CH OP(O) (R) (OM) (64%) R represents the p-fluorophenyl radical (FC H M represents an equivalent of an alkali earth metal and the yield is indicated in parentheses.

p-Fluorophenylphosphonic oxide reacts with all the other alcohols mentioned in Examples 1 to 15 to yield the corresponding p-fluorophenylphosphonic monoesters.

The p-fluorophenylphosphonic oxide is prepared as follows according to the equation:

3 8 grams (0.216 mole) of p-fluorophenylphosphonic acid and 64 grams (0.3 mole) of p-fluorophenylphosand the precipitate (p-fluorophenylphosphonic oxide) filtered off. The filtrate is left again for two days at 5 degrees centigrade and a second amount of p-fluorophenylphosphonic oxide is filtered oil. The operation is repeated until no further precipitation occurs (after concentration of pure p-fiuorophenylphosphonic oxide, melting point 109-111 degrees centigrade, are obtained (yield 88%).

(C H O FP) Calculated: F, 12.0%; P, 19.6%; equivalent weight, 158.1. Found: F, 12.4%; P, 19.3%; equivalent Weight, 160.

What is claimed is:

1. A compound represented by the formula 11 wherein R is selected from the group halogenophenyl and nitrophenyl, R is alkyl of 1 to 18 carbon atoms carrying one or more halogen substituents, and M is selected from the group consisting of alkali metals and alkaline earth metals.

2. A compound in accordance with claim 1 wherein R is selected from the group consisting of phenyl and p-fiuorophenyl.

3. A compound in accordance with claim 1 wherein R is alkyl of 1 to 8 carbon atoms.

4. The compounds of the formula:

consisting of phenyl,

1 2 6. The compound of the formnlaif 5 o CHr-CHrCHrCHzCl References Cited UNITED STATES PATENTS 2,360,302 10/1944 Etzler ct a1. 260-961 X FOREIGN PATENTS 823,293 10/1951 Germany.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,350,480 October 31, 1967 Emile Cherbuliez et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, lines 45, 54, and 55; column 8, lines 63 and 68; and column 9,

line 39, "centrigrade" each occurrence, should read Centigrade Column 2, line 34, "qutie should read quite line 56, "sensitve" should read sensitive Column 3, line 29, after "metal" insert salt line 65, "methyl should read menthyl Column 5, lines 54 to 57, the formula should appear as shown below:

Column 6, lines 20 to 23, the formula should appear as shown below:

(Ill/OM C H P OCH CF -CHF Column 7, line 55, "aslt should read salt Column 10, line 9 the formula should read CCl CH[OP (O) (C H (OBa )-CH line 24, the formula should read (CH C0? (O) (R) (OM) line 25, the formula should r '(C H5) (CH3)COP (O) (R) (OM) Column ll, lines 12 to 15, the formula should appear as shown below:

same column 11, lines 16 to 20, the formula should appear as shown below:

Column 12, line 1, formuloff should read formula same column 12, lines 3 to 6, the formula should appear as shown below:

OCH CH CH CH Cl Signed and sealed this 10th day of March 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

1. A COMPOUND REPRESENTED BY THE FORMULA 